Work performance has long been the most important dependent variable in the fields of I/O Psychology and Organizational Behaviors. However, there had been little research accumulation especially about the validity of the construct until the 1980s, which resulted in many undesirable phenomena such as the proliferation of applied research without validity study, the narrow perspective on the construct, and the widening gab between the objective performance scales preferred by researchers and the subjective ones by organizations. Fortunately, there has been a great development in the theory of performance since the 1990s. This paper reviews its recent theoretical advancements, focusing specifically on the validity study of work performance, its four dimensions, and the future research direction.